The present invention relates to a recovery system in which data is transferred between storage subsystems for the purpose of preserving data in case of a disaster.
A technique for adding a new computer to a network is disclosed in Japanese Unexamined Patent Application Publication No. 2002-278769. The disclosed technique is particularly applicable to a case where a second computer is added to a network system that comprises a first computer, a first storage subsystem in which an operating system (hereinafter OS) is stored, and a second storage subsystem in which a copy of data stored in the first storage subsystem is stored. According to the technique, the first computer modifies the settings of the second storage subsystem, and it assigns the second storage subsystem to the second computer so that the OS stored in the second storage subsystem can be installed in the second computer.
Moreover, a method for setting up a high-availability system, which employs a common disk, in a storage subsystem is disclosed in “VERITAS Cluster Volume Manager and VERITAS Cluster File System: a new VERITAS volume management and file system technology for a cluster environment (http://www.veritas.com/jp/products/pdfs/cvm_cfs_wp.pdf)”. According to this method, a slave computer detects a common disk included in a storage subsystem, and it reads volume information from the common disk so as to define a common volume to be assigned to a slave computer included in a high-availability configuration. Consequently, the slave computer included in the high-availability configuration autonomously recognizes the volume.
According to the technology disclosed in Japanese Unexamined Patent Application Publication No. 2002-278769, after the second computer is added, the first computer modifies the settings of the second storage subsystem. In this case, if a fault occurs in the first computer, the second computer cannot use the second storage subsystem. Moreover, if the network system is used as a disaster recovery system, both the first and second computers are mandatory. Therefore, an inexpensive disaster recovery system cannot be provided.
Moreover, according to the technology disclosed in “VERITAS Cluster Volume Manager and VERITAS Cluster File System: a new VERITAS volume management and file system technology for a cluster environment,” the slave computer can recognize the common volume autonomously. However, the master computer and slave computer must share the same storage subsystem. Therefore, the technology cannot be adapted to a disaster recovery system as it is. The adaptation of the technology disclosed in “VERITAS Cluster Volume Manager and VERITAS Cluster File System: a new VERITAS volume management and file system technology for a cluster environment” to a disaster recovery system will be discussed.
As far as a disaster recovery system is concerned, an entity of a disk drive is often different between a primary site and a secondary site. The consistency in an emulation type that is a category to which a disk drive belongs when assigned to a computer or in a storage capacity of a disk drive between the primary and secondary storage systems is not guaranteed. In this situation, the computer in the secondary site cannot recognize a volume autonomously.
Moreover, when an application, such as a database application that runs in the primary site, is to be continuously run in the secondary site, the settings of the secondary site must be determined manually. It is therefore impossible to continuously and swiftly run the application.